1. Field of the Invention
This invention relates to an apparatus and method useful for positioning a patient's leg during hip surgery and, more particularly, to an improved leg support and displacement system for use with arthroscopic observation equipment.
2. Description of the Related Art
Surgery on a hip joint, which is deep within surrounding tissue, is best planned when the surgeon has been able to observe bones that make up the joint and their position and condition. This observation is possible through diagnostic arthroscopic surgery which has proven beneficial to patients because it allows surgeons to visualize most areas of the acetabulum, ligamentum terras and femoral head. Inspection of the joint surfaces during arthroscopy provides a basis for determining when open osteotomy is a suitable treatment option, which decreases the need for the more radical total hip replacement.
Distraction of the femoral head from the hip joint is necessary to provide the physician with access to the joint. Once the femur is separated from the hip joint, access to various surface aspects of the hip joint and femoral head requires controlled movement of the patient's leg in a full range of motion and fixation of the leg in selected positions. Because of the shape of the femoral head and the depth and tightness of the joint, precise manipulation of the patient's leg to allow sufficient access is difficult to achieve. The soft tissue of the joint and points on the patient's leg that are subject to applied forces during distraction are easily damaged.
Orthopedic limb support and traction devices have been previously suggested for use in manipulating the leg during arthroscopic hip surgery. U.S. Pat. No. 3,087,489 to Gilbert describes an orthopedic device with a T-shaped frame which supports traction and limb holding members. The device is cumbersome and impedes a surgeon's access to the patient's joint.
U.S. Pat. No. 5,027,799 to Laico describes a limb holding device attachable to an operating table to immobilize the patient's arm or leg during arthroscopic or other surgery. An H-shaped frame supports a fork-like limb support member. Force is placed on the perineum and inner thigh with the use of a perennial post mounted to the operating table to separate the femur from the hip joint. Adjustable clamps and a crank and screw are used to manipulate and vary the position of the patient's limb.
The Laico device is difficult to set up, having two major assemblies that require alignment with the operating table and four attachment points to the operating table. Use of a perennial post to separate the femur from the hip joint is believed to cause an invasive point load on the patient's inner thigh, which could affect nerves and blood vessels located in that area and cause possibly tissue damage.
These devices are also troublesome because they allow only limited exposure to the inner surfaces of the hip joint and femoral head. Neither do these devices utilize mechanical advantages with efficiencies designed to increase ease and accuracy in manipulating the leg.
Thus, there is a need for a device that is easy to set up and allows controlled, precise manipulation of the patient's leg to access the inner surfaces of the hip joint and femoral head with minimal tissue damage.